1. Field of the Invention
This invention relates to temperature-proof shoes and a method of making same, and particularly to temperature-proof shoes having an excellent heat retaining property by the use of composite sheets of thick leather and heat insulating material and also having an elegant finished form like ordinary men's shoes.
2. Description of the Prior Art
Temperature-proof shoes known conventionally to have an outstanding heat retaining effect are those using a three layer structure of leather with closed cell polyurethane foam provided as an intermediate layer. These temperature-proof shoes are provided with the temperature-proofing property by heat insulating effect shown by the closed cell polyurethane foam.
However, as shown in a partial longitudinal section in FIG. 4, the shoes using the three layer structure composed of a leather facing 11, a leather lining 12 and an intermediate layer made of closed cell polyurethane foam 13 had certain problems including that, during the tuck-in forming in the process prior to the fastening of main sole, the soft and weak polyurethane foam layer 13 loses its resiliency or its foam is crushed by getting excessively pressed by the peripheral edge of the bottom of a form block A or by the peripheral edge of an insole 14, thereby spoiling the wearing comfort, and that an aesthetically satisfactory contour line cannot be obtained for the portion where the leather is folded along the bottom peripheral edge of the form block A and the peripheral edge of the insole board 14 (hereafter, this portion will be called the tucked-in bent portion). Consequently, tuck-in forming has required skilled techniques which depend on many years of experience and a delicate sense of a seasoned craftsman. Thus, it has been very difficult to obtain well-finished and high quality products.
Also, as shown in a partial longitudinal section in FIG. 6, when the conventional method of sewing the insole board 14 to the main sole 17 by the roll-in type topstitching, because the polyurethane foam layer 13 is thick, a proper form could not be obtained, and also, the intrusion of water from outside through the seam can not be prevented.